PHP recursively generates tree-like instance code

This article introduces the example code for Recursive Generation of tree lines in PHP.

1. <? Php
2. Header ("content-type: text/html; charset = UTF-8 ");
3. $ Connect = mysql_connect (localhost, root, 123456 );
4. Mysql_select_db ("wz ");
5. Mysql_query ("set names utf8 ");
6. // Obtain the top node
7. $ SQL = "select id, name, ischild from tree where parent = 0 order by id asc ";
8. $ Result = mysql_query ($ SQL );
9. While ($ row = mysql_fetch_array ($ result ))
10. {
11. Extract ($ row );
12. // If a subnode exists, add an event to it to expand or close the subnode.
13. $ Icon = $ ischild? "<A href = javascript.: expand (" div $ id ");> </a> ":"-";
14. $ Name = $ icon. $ name;
15. Echo "<div id = div". $ id. ">". $ name;
16. If ($ ischild)
17. {
18. // Recursively retrieve nodes
19. GetNode ($ id, 0 );
20. }
21. Echo "</div> ";
22. }
24. Function getNode ($ id, $ level)
25. {
26. $ SQL = "select id, name, ischild from tree where parent = $ id order by id asc ";
27. $ Result = mysql_query ($ SQL );
28. $ Level;
29. While ($ row = mysql_fetch_array ($ result ))
30. {
31. Extract ($ row );
32. $ Icon = $ ischild? "<A href = javascript.: expand (" div $ id ");> </a> ":"-";
33. $ Name = $ icon. $ name;
34. Echo "<div id = div". $ id. ">". echoChar ("", $ level). $ name;
35. If ($ ischild)
36. {
37. GetNode ($ id, $ level );
38. }
39. Echo "</div> ";
40. }
41. }
43. Function echoChar ($ char, $ num)
44. {
45. For ($ I = 0; $ I <$ num; $ I)
46. {
47. $ StrChar. = $ char;
48. }
49. Return $ strChar;
50. }
51. ?>
52. <Script language = "javascript">
53. Function expand (id)
54. {
55. Var obj = document. getElementById (id). childNodes;
56. For (var I = 0; I <obj. length; I)
57. {
58. If (obj [I]. nodeName = "DIV ")
59. {
60. Switch (obj [I]. style. display)
61. {
62. Case "":
63. Case "block ":
64. Obj [I]. style. display = "none ";
65. Break;
66. Case "none ":
67. Obj [I]. style. display = "block ";
68. Break;
69. }
70. }
71. }
72. }
73. </Script>